See note on 1Ti 1:4 for prosechō and muthois, only here we have Jewish (Ioudaikois) added. Perhaps a reference to the oral traditions condemned by Christ in Mar 7:2-8. See also Col 2:22, apparently Pharisaic type of Gnostics.
Who turn away from the truth (apostrephomenōn). Present middle (direct) participle of apostrephō, “men turning themselves away from the truth” (accusative according to regular idiom). “The truth” (1Ti 4:3) is the gospel (Eph 4:21).